Seems intended. Something about earning 2 special missions at once just doesn't seem right.
People are likely just playing the tb the wrong way trying to exploit reward structure. Seems like the devs put a fail safe in place to prevent people from taking advantage of rewards.
These cases are usually the fault of players for playing wrong.
Let me explain...
If you do 2 special missions in 1 day your messing up your whole guild so just tell all 50 people which mission to do and dont let anyone do the other one, make sure you get a star and u get rewards. Guilds poorly organized are penalized. It works... this is how players should be playing. Anything outside of this approved approach is likely viewed as trying to game the system by the devs, so they blocked rewards.
This has been reported a lot and I'm not sure that it has been confirmed as a bug so going with wai until I hear differently.
